 /*******************************************************************************
  * Copyright (c) 2004, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.themes;

 import java.util.Hashtable ;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExecutableExtension;
 import org.eclipse.swt.graphics.RGB;

 /**
  * A resuable <code>IColorFactory</code> that may be used to blend two colors.
  * The colors to blend are specified as per method number two in
  * {@link org.eclipse.core.runtime.IExecutableExtension}.
  * <p>
  * Example usage:
  * <br/>
  * <code>
  * &lt;colorDefinition
  * label="Red/Blue Blend"
  * id="example.redblueblend"&gt;
  * &lt;colorFactory
  * plugin="org.eclipse.ui"
  * class="org.eclipse.ui.themes.RGBBlendColorFactory"&gt;
  * &lt;parameter name="color1" value="255,0,0" /&gt;
  * &lt;parameter name="color2" value="COLOR_BLUE" /&gt;
  * &lt;/colorFactory&gt;
  * &lt;/colorDefinition&gt;
  * </code>
  * </p>
  *
  * <p>
  * The color values may be specified as RGB triples or as SWT constants.
  * </p>
  *
  * @see org.eclipse.swt.SWT
  * @since 3.0
  */
 public class RGBBlendColorFactory implements IColorFactory,
         IExecutableExtension {

     private String color1, color2;

     /* (non-Javadoc)
      * @see org.eclipse.ui.themes.IColorFactory#createColor()
      */
     public RGB createColor() {
         if (color1 == null && color2 == null) {
             return new RGB(0, 0, 0);
         } else if (color1 != null && color2 == null) {
             return ColorUtil.getColorValue(color1);
         } else if (color1 == null && color2 != null) {
             return ColorUtil.getColorValue(color2);
         } else {
             RGB rgb1 = ColorUtil.getColorValue(color1);
             RGB rgb2 = ColorUtil.getColorValue(color2);
             return ColorUtil.blend(rgb1, rgb2);
         }
     }

     /**
      * This executable extension requires parameters to be explicitly declared
      * via the second method described in the <code>IExecutableExtension</code>
      * documentation. This class expects that there will be two parameters,
      * <code>color1</code> and <code>color2</code>, that describe the two colors
      * to be blended. These values may either be RGB triples or SWT constants.
      *
      * @see org.eclipse.core.runtime.IExecutableExtension#setInitializationData(org.eclipse.core.runtime.IConfigurationElement, java.lang.String, java.lang.Object)
      */
     public void setInitializationData(IConfigurationElement config,
             String propertyName, Object data) throws CoreException {

         if (data instanceof Hashtable ) {
             Hashtable table = (Hashtable ) data;
             color1 = (String ) table.get("color1"); //$NON-NLS-1$
 color2 = (String ) table.get("color2"); //$NON-NLS-1$
 }
     }
 }

